Relay circuit



March 1938. w. F. K'ANNENBERG 2,111,632

RELAY c lRCU I T Filed Dec. 19, 1936 INVENTOR W E KANNENBERG ATTORNEY Patented Mar. 22, 1938 PATENT OFFICE RELAY CIRCUIT Walter F. Kannenberg, Rutherford, N. J., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application December '19, 1936, Serial No. 116,838

ii Claims ((31. 175-320) This'invention relates to electromagnetic apparatus and more particularly to a circuit for delaying the energization of an electromagnetic device and thereby, in the case of a relay, delaying the attraction of its armature for a considerable period of time after the circuit is established.

The usual means for delaying the operation of a relay involves a short-circuited winding or copper slug on the relay core or a special construcl0 tion of the relay. It is the object of the present invention to provide a novel and improved means for operating a relay after a definite and controllable interval, whereby the relay may be of standard and simple construction. A further ob- 16 ject of the invention is in the provision of a relay controlling circuit whereby a much longer delay interval may be attained than heretofore possible with a relay having a copper slug or shortcircuited winding.

In accordance with the present invention, these objects are attained by employing a controlling circuit for the relay including a copper-oxide bridge, a condenser, an asymmetric resistance and sources of potential. The relay is bridged in -21; series with a biasing battery across the output terminals of the bridge. One input terminal of the bridge is connected to one terminal of the condenser and through an asymmetric resistance or copper-oxide rectifier to one terminal of a resistance and the other input terminal of the bridge is connected to the other terminal of the condenser and to the other terminal of the resistance whereby the condenser is connected directly across the input of the bridge and the resistance is shunted across the bridge through the rectifier. The resistance is connected in series from a source of 130 volt negative potential through a secondary resistance to the armature contact of a control relay and is completed either to a source of 130 volt negative potential or 130 volt positive potential dependent upon whether the controlv relay is unoperated or operated.

For a clearer comprehension of the invention and the manner in which it functions, reference may be had to the following detailed description taken in connection with the accompanying drawing.

The relay whose delayed operation is to be controlled is shown at I. This relay may be of the usual polarized type having no provision in its construction for delaying its response. The operation of thirelay is controlled by any desired means as for example by the relay 2. The winding of relay l is bridged in series with the biasing 66 battery 3 across the output terminals 4 and 5 of the bridge 6. The four arms of the bridge 6 comprise the copper-oxide rectifiers I, 8, 9 and i0 poled as indicated. 4

The input terminal ll of the bridge is connected to oneterminal of condenser I3 and through the asymmetric res stance i 4, which may be a copper-oxide rectifier, to one terminal of resistance i5. The other input terminal 12 of the bridge is connected to the other terminal of condenser i3 and to the other terminalof resistance l-5., Thus the condenser i3 is connected directly across the input terminals of the bridge and the resistance i5 is shunted across the input terminals of the bridge through the rectifier I4.

The resistance 15 is included in a control circuit extending from the negative or ungrounded terminal of 130 volt battery 16 through resistance l5, resistance l! to the armature contact of control relay 2 and is completed either to the negative or ungrounded terminal of 130 volt bat-- tery 18, which may be the same battery as the battery l6, or to the positive or ungrounded terminal of 130 volt battery [9 dependent upon whether relay 2 is unoperated or operated.

The circuit functions in the following manner: With the control relay 2 unoperated, negative potential is connected to eachterminal of resistance. l5, condenser i3 is uncharged, and both input terminals I! and 62 of the bridge 6 are at the same potential. Current from the biasing battery 3 will, however, flow from the positive terminal thereof through the winding of relay l, output terminal 4 of the bridge and thence by I parallel paths over arms 'I and 8 and arms 9 and ill of the bridge to output terminal 5 and to the negative terminal of battery 3. Since, however,

the current tends to how in the high resistance direction through the rectifiers comprising the arms of the bridge, the biasing efiect of battery 3 will only be sufficient to insure that the armature contact of relay i will be held against its back contact.

When the control relay 2 operates to close its front contact, batteries i6 and i9 are connected in series aiding relationship and current will flow from the positive terminal of battery l9 over the front contact of relay 2.? through resistances iii and 15 to the negative terminal of battery Iii and by one parallel path through the rectifier I4 and condenser l3 and by a second parallel path through rectifier l4, input terminal ll, arm 9 and terminal 4 of bridge 6, through the winding of relay l and biasing battery 3, terminal 5, arm 8 and terminal. H of bridge 6. The current flowing through the winding of relay I over the path Just traced, through rectifier I4 is in opposition to the biasing current from battery 3 and, although in the proper direction to cause the operation of relay I, is oi insuificient strength since the rectifier I4 is so poled as to ofier high resistance to the flow oi current.

Condenser I3 now charges slowly since the rectifier I4 is poled to present a high resistance in the charging circuit thereof extending as previously traced from battery I5 through resistance II, rectifier I4 and condenser II to battery I6. As soon, however, as condenser I3 reaches its full charge, the difierence oi potential between terminals II and I2 of the bridge will be such that sufiicient current will fiow through the bridge to overcome the potential oi. the biasing battery 3 and relay I will thereupon operate. The excess of current required to overcome the biasing eflect of battery I and to cause relay I to operate may be very slight.

The delay in the operation 01' relay I after the operation of relay 2 is thus determined by two factors; first, the charging time of condenser I3 as determined by the high resistance characteristic oi rectifier I4 and second, by the potential of the biasing battery 3. This delay may thus be regulated by changing the resistance value 01' rectifier I4, by changing the potential or battery I or by varying the capacitance of condenser II. To render the capacitance of condenser I3 easily alterable, this condenser might be made of the well-known adjustable type.

When control relay 2 releases the negative 130 volt battery II is connected over its back contact through resistances II and" to the negative 130 volt battery "and, with the two terminals oi resistance I! thus at the same potential, condenser IS discharges quickly in a path through rectifier I4 in its low resistance direction and through resistance I5. Biasing battery I is now eiIective to quickly release relay I.

The relay I might also be of the simple nonpolarized type in which event the normal eiIect oi the biasing battery I would be to energize the winding thereof insufiiciently to move its armature contact from engagement with its back contact. When, howeveqcurrent fiows through the bridge in response to'the operation of relay 2 and reaches its maximum value when condenser I3 becomes fully charged, this current will op pose the current flowing from biasing battery 8 and will be of suificient magnitude to cause relay I to move its armature contact into engagement with its front contact. Thereafter, when condenser I3 quickly discharges in. response to the release 0! relay 2, current will cease to flow through the bridge and relay I will therefore quickly release.

From the foregoing description, it will be apparent that provision is made for rendering relay I slow to operate following the operation of relay 2 and quick to release following the release of relay I. While batteries It, II and I! have been disclosed as having a particular voltage, batteries of other voltage might be used commensurate with the voltage oi biasing battery 8 and the values 0! other elements 01 the circuit.

What is claimed is:

1. In combination, a first source of current, a

condenser, a rectifier bridge havingits input terminals connected across said condenser, a source of biasing current, an electromagnetic device 75 having its winding connected in series with said source oi biasing current across the output terminals of said bridge, and means for connecting said first source 01' current with said condenser and with the input terminals 01' said bridge whereby when said condenser becomes charged, current or sufilcient strength will fiow through said bridge to overcome said source of btasing current and to operate said electromagnetic device.

2. In combination, a first source of current, a condenser, a rectifier bridge having its input terminals connected across said condenser, an electromagnetic device, a source of biasing current connected in series with the winding of said electromagnetic device across the output terminals of said bridge and oi such potential as to just hold said electromagnetic device in its unoperated condition, and means for connecting said first source of current with said condenser and with the input terminals of said bridge, whereby when said condenser becomes charged,

current of sumcient strength will flow through said bridge to overcome said source 01 biasing current and to operate said electromagnetic device.

3. In combination, a first source of current, a condenser, a rectifier bridge having its input terminals connected across said condenser, a source of biasing current, an electromagnetic device having its winding connected in series with said source 01' biasing current across the output terminals oi said bridge, a control circuit connected with said condenser and with the input terminals or said bridge including a resistance element which presents a high resistance to the fiow oi. charging current to said condenser, and means for connecting said first source 01' current to said control circuit, whereby when said condenser becomes charged, current of sufiicient strength will flow through said bridge to overcome said source of biasing current and to operate said electromagnetic device.

4. In combination, a first source 0! current, a condenser, a rectifier bridge having its input terminals connected across said condenser, a source 01 biasing current, an electromagnetic device having its winding connected in series with said source 01' biasing current across the output terminals of said bridge, a control circuit including a resistance, said resistance being bridged across said condenser and across the input terminals of said bridge through a resistance element which presents a high resistance to the fiow of current through said bridge and to the fiow oi charging current to said condenser, and means (or connecting said first source oi current to said control circuit, whereby when said condenser becomes charged, current of sufiicient strength will fiow through said bridge to overcome said source 01 biasing current and to' operate said electromagnetic device.

5. In combination, a first source or current, a condenser, a rectifier bridge having its input terminals connected across said condenser, a source or biasing current, an electromagnetic device having its winding connected in series with said source or biasing current across the output terminals 01 said bridge, a control circuit connected with said condenser and with the input terminals 01' saidbridge including a resistance element which presents a high resistance in the charging path anda low resistance in the discharging path of said condenser, and means eiiective upon its operation for connecting said first source of current to said control circuit for establishing the charging path of said condenser and upon its release for establishing the discharging path of said condenser, whereby the operation oi said electromagnetic device is' de layed following the operation of said means until said condenser becomes charged and its release follows immediately after the release of said means.

6. In combination, a first source of current, a condenser, a rectifier bridge having its input terminals connected across said condenser, a source 01 biasing current-an electromagnetic device having its winding connected in series with said source of biasing current-across the output terminals of said bridge, a control circuit including a resistance having its terminals normally maintained at the same potential, said resistance being bridged across said condenser and across the input terminals of said bridge through a resistance element which presents a high resistance to the flow of current through said bridge and to the fiow'oi charging current through said condenser and presents a low resistance to the discharge current from said condenser through said resistance, and means eflective upon its operation for connecting said first source of current to said control circuit for establishingjthe charg- -ing path of said condenser wherebywhen said condenser becomes charged, current 01' sufiicient strength will'fiow through said bridge to overcome said source 01 biasing current and to operate said electromagnetic device, and eflective upon its release -for rendering the discharge path of said condenser efiective whereby said electromagnetic device quickly releases. I

' WALTER F. KANNENBERG. 

